家族性乳腺癌和健康遗传高危人群BRCA1/2基因突变研究

目的:研究中国汉族女性家族性乳腺癌患者和健康遗传性高危人群的BRCA1/2基因突变特征。方法:研究对象为2013年12月~2014年10月于解放军307医院乳腺外科确诊的54例汉族家族性乳腺癌患者及24例健康遗传性高危人群,应用PCR-DNA直接测序法检测乳腺癌易感基因BRCA1和BRCA2的全编码外显子基因序列。结果:54例家族性乳腺癌患者中共发现8例致病性突变,突变类型均为单个碱基置换,BRCA1和BRCA2的总突变率为14.8%,BRCA1突变率为11.1%,BRCA2突变率为3.7%;其中,三阴性乳腺癌患者BRCA总突变率高于非三阴性乳腺癌患者的总突变率(28.6%vs 12.8%),差异具有统计学意义(P0.05)。24例遗传性高危人群中共发现2例致病性突变,均为BRCA1基因突变,突变率为8.3%。结论:用BRCA1/2突变检测"金标准"的一代测序法再次发现在中国汉族女性家族性乳腺癌中存在的BRCA1/2突变,与三阴性乳腺癌有关,并发现碱基置换突变也是重要的突变类型;在健康遗传性高危人群中存在一定比例的BRCA1突变,值得关注。     

山东东部地区家族性和早发性乳腺癌BRCA1基因突变的研究

目的:研究家族性和早发性乳腺癌BRCA1基因突变情况.方法:选取52例来自不同家系家族性和早发性乳腺癌患者,提取外周血基因组DNA,对BRCA1基因的全部编码序列及外显子与内含子的拼接区进行PCR基因扩增,扩增产物经变性高效液相色谱分析(DHPLC)除筛后,对发现异常的片断进行DNA直接测序证实.结果:在52例家族性和早发性乳腺癌患者中发现4例(7.7%)BRCA1致病性突变(2257C＞G,2229del1AA,3413de1T),其中BRCA1的2229de1AA在两个不同的家系重复出现.3413de1T突变未在Breast Cancer Information Core(BIC)数据库和相关的文献报道过.家族性乳腺癌突变率为12%(3/25);单纯早发性乳腺癌突变率为3.7%(1/27).结论:BRCA1突变在山东东部地区家族性乳腺癌的发病中发挥重要作用,对具有家族史的乳腺癌家系进行BRCA1基因突变筛查具有重要意义.     

HPV16 变异体在新疆地区宫颈癌及癌前病变中的分布研究

目的:研究新疆地区HPV16 E6、E7、LCR基因突变情况,分析HPV16变异体在宫颈癌及癌前病变发生发展中的作用。方法:选择HPV16阳性的宫颈癌及癌前病变患者,提取基因组DNA,利用PCR扩增HPV16 DNA E6、E7基因及LCR区核苷酸片段,正反向测序。与HPV16基因序列分析比对,分析核苷酸突变位点。结果:E6基因突变率为80.00%(92/115)主要突变位点T350G(59.78%)、T178G(18.47%);E7突变率为54.78%(63/115),主要突变位点A647G(33.33%)、T846C(26.98%);LCR突变率为23.48%(27/115),主要突变位点为C24T(74.07%)、C13T(25.92%)。维吾尔族T350G突变率较汉族妇女显著升高,而汉族A647G、T846C、C24T突变率显著高于维吾尔族,差异具有统计学意义(P0.05)。维吾尔族宫颈癌组T350G突变率显著高于炎症组(P0.05),且随病变严重程度增加突变率上升,汉族T350G、A647G、T846C、C24T突变率炎症组、宫颈病变组显著高于宫颈癌组(P0.05),维吾尔族C24T突变率炎症组显著高于宫颈癌组(P0.05),差异均具有统计学意义(P0.05)。结论:HPV16E6、E7突变可能与宫颈病变进展有关,T350G突变可能是维吾尔族宫颈癌高发的原因之一。     

新疆女性乳腺癌657例临床病理分析

目的:比较维族与汉族乳腺癌患者的临床病理信息,旨在了解两民族之间乳腺癌临床病理特征的差异。方法:收集汉族病例407例,维族病例250例,对临床病理资料、,应用免疫组化En Vision两步法检测ER、PR、Her-2、BRCA1进行对比分析。结果:汉族及维族乳腺癌患者的年龄、淋巴结转移情况无统计学差异(P0.05),汉族及维族患者乳腺癌的肿瘤大小、肿瘤组织学分级、ER、PR、Her-2及BRCA1的表达有统计学差异(P0.05),维汉民族间三阴性乳腺癌的比例有显著统计学差异(P=0.0000)。维汉民族三阴性乳腺癌与BRCA1的表达存在相关性。结论:维汉民族间乳腺癌的临床病理特征存在差异,维族患者三阴性乳腺癌明显多于患者患者,维汉民族患者三阴性乳腺癌均与BRCA1基因突变有关。     

三阴乳腺癌P53突变热点及与预后的关系

目的:探讨三阴乳腺癌(TNBC)P53基因热点突变的情况及其与预后的关系。方法:选取2007年1月至2010年12月四川省人民医院收治的71例TNBC患者作为研究对象,采用免疫组化法检测71例TNBC患者手术石蜡标本的P53蛋白表达情况,采用ADx-ARMS方法检测P53基因突变热点情况,并分析两者与TNBC复发转移的关系。结果:71例患者总共有14例出现复发或转移,复发或转移发生率为19.7%。71例患者P53蛋白阳性表达率为69.0%,P53蛋白表达阳性患者的复发或转移率为18.4%,与P53蛋白表达阴性患者的复发或转移率22.7%比较,差异无统计学意义(P0.05)。总共有5例患者检出P53热点突变,P53热点突发生率为7.0%。P53热点突变全部都在P53蛋白阳性表达的患者中检出,而有P53热点突变的患者均没有出现复发或转移。结论:P53热点突变在TNBC患者中发生率不高,均出现在有P53蛋白阳性表达的患者中,而出现P53热点突变的患者预后较好。     

K-ras基因突变及表达与胰腺癌的关系

目的:探讨K-ras基因突变及蛋白表达对胰腺癌的诊断价值。方法:采用突变等位基因特异性扩增(PCR-MASA)检测31例胰腺癌和22例非胰腺癌石蜡包埋组织中K-ras基因12密码子点突变情况,并通过免疫组化法检测其K-ras蛋白的表达。结果:胰腺癌患者K-ras基因12密码子点突变率为80.6%(25/31),K-ras蛋白表达阳性率为87.1%(27/31);而非胰腺癌患者K-ras基因12密码子点突变率为27.3%(6/22),K-ras蛋白表达阳性率31.8%(7/22)。胰腺癌患者K-ras基因突变率及K-ras蛋白表达阳性率均明显高于非胰腺癌患者(P均0.05)。K-ras基因突变与其蛋白表达呈正相关(r=0.542,P0.05),而与胰腺癌患者的性别、年龄、肿瘤部位、肿瘤大小、临床分期及分化程度等临床病理特征均无显著相关性(P均0.05)。结论:胰腺癌K-ras基因突变的发生率升高,且K-ras蛋白表达异常上调,二者可能有助于胰腺癌的诊断。     

BRCA1、PTEN、Rb、C-myc和C-myb在乳腺癌中的异常表达及临床意义探讨

目的 探讨BRCA1、PTEN、Rb、C-myc、C-myb蛋白异常表达在乳腺癌发生、发展中的作用及其临床意义.方法应用免疫组织化学S-P法检测150例乳腺癌、20例不典型增生和30例良性增生性病变组织中BRCA1、PTEN、Rb、C-myc、C-myb蛋白的表达;结合临床病理指标进行分析.结果 乳腺癌组织和不典型增生组织中 BRCA1、PTEN、Rb、C-myc、C-myb蛋白表达与良性增生性病变组织中表达均具有显著性差异(P<0.05).BRCA1蛋白失表达率随乳腺癌组织学分级的增高而增高,在年龄<50岁和ER(雌激素受体)阴性时BRCA1蛋白失表达率增高.PTEN蛋白的失表达与淋巴结转移、ER失表达有关(P<0.05).Rb蛋白在乳腺癌Ⅲ级中失表达率较高,但无统计学差异(P＞0.05).C-myc蛋白的过表达与组织学分级、淋巴结转移及病理类型有关(P<0.05).C-myb蛋白的过表达与乳腺癌组织学分级有关(P<0.05).结论 BRCA1、PTEN、Rb、C-myc、C-myb蛋白异常表达均在乳腺癌的发生过程中起作用;PTEN、C-myc、C-myb 蛋白的异常表达参与了乳腺癌的浸润和转移.     

江浙沪地区乙肝病毒B、C基因型S基因突变及选择压力分析

目的系统分析江浙沪三地的乙肝病毒B、C基因型S基因突变和选择压力情况,以期为乙型肝炎的防治提供理论依据。方法采用NCBI数据库提供的乙肝病毒序列,分为B、C基因型两组,分析突变情况,同时采用Datamonkey进行选择压力分析和Bioedit进行氨基酸置换熵值分析。结果S基因226个氨基酸位点突变分析中,产生突变有位点122个,位点突变率C基因型(45.58%)高于B基因型(30.09%)(χ~2=11.523,P=0.001);总突变率C基因型(1.36%)高于B基因型(0.80%)(χ~2=46.642,P=0.000);α决定簇突变率C基因型(2.40%)高于B基因型(0.96%)(χ~2=20.524,P=0.000)。B基因型α决定簇突变率高于总突变率(χ~2=0.735,P=0.391);C基因型α决定簇突变率高于总突变率(χ~2=44.467,P=0.000)。B基因型氨基酸突变最多的位点为200、213、161和21位点,C基因型氨基酸突变最多的位点为126、68、3、53和194位点。两个基因型dN/dS均值均小于1。B基因型没有发现正向选择位点,发现8个负向选择位点。C基因型发现7个正向选择位点,17个负向选择位点。B基因型仅发现一个易突变位点(200位),C基因型也仅发现一个易突变位点(126位),大多数氨基酸位点熵值0.4。结论江浙沪地区S基因突变率水平较低,其中C基因型位点突变率、α决定簇突变率和总突变率高于B基因型,α决定簇突变率高于总突变率。C基因型经历外界环境免疫选择压力和自身进化压力双重影响,自身进化压力强于外界环境免疫选择压力;而B基因型主要遭受自身进化压力。尤其要格外关注C基因型的进化进程。     

PKP2基因突变与致心律失常性右心室心肌病相关

为了探讨血小板亲和蛋白2(PKP2)基因突变与致心律失常性右心室心肌病(ARVC)的关系。选取2011年2月至2017年5月在我院治疗的ARVC患者41例(ARVC组),同时选取50例健康志愿者作为对照组,采用PCR扩增PKP2基因DNA片段,检测PKP2基因突变以及单核苷酸多态性(SNP)位点基因型及等位基因频率。结果显示,ARVC组PKP2基因突变率为29.27%,明显高于对照组的0.00%(p0.05);12例PKP2基因突变共发现了7个突变位点,包括3个错义突变、2个无义突变、1个缺失突变和1个剪接位点突变;ARVC组PKP2基因突变患者室速、LBBB型电轴向上形态室速比例均为83.33%,明显高于非突变患者的37.93%和41.38%,差异具有统计学意义(p0.05);PKP2基因共有2个SNP位点,包括P273和L366P位点,ARVC组和对照组2个SNP位点基因型频率及等位基因频率差异无统计学意义(p0.05)。ARVC患者PKP2基因突变较高,与患者迅速发作有关,而PKP2基因的两个SNP位点(P273P和L366P)与ARVC发病无关。     

BRCA1 基因启动子区SNPs 与散发性乳腺癌易感性的相关研究

目的:探讨BRCA1基因启动子区rs11655505、rs73625095位点单核苷酸多态性与散发性乳腺癌易感性的关系。方法:采用ASA-PCR方法对200例乳腺癌患者(均经病理确诊)及200例正常女性BRCA1基因启动子区rs11655505(A/G)、rs73625095(A/G)位点单核苷酸多态性(SNP)进行分析,并将其PCR产物进行测序。结果:乳腺癌患者BRCA1基因启动子区rs11655505位点的A/G基因型频率为75%,显著高于正常人的40%;A/A基因型频率为7%,G/G基因型频率为18%,分别低于正常人的30%、30%。此位点的A或G等位基因在乳腺癌病例组及对照组中均无差别(x2=2.427,P=0.119);rs73625095位点的A/G基因型频率为68%,显著高于正常人的15%;G/G基因型频率为32%,低于正常人的84%;乳腺癌病例组中BRCA1基因启动子区rs11655505、rs73625095位点的A/G基因型与淋巴结转移与否相比,差别均有统计学意义(x2=7.321,P=0.026、x2=4.782,P=0.029)。结论:BRCA1基因rs11655505位点、rs736...     

新疆维、汉P-gp、MRP1、GST-π与宫颈癌新辅助化疗疗效的相关性研究

目的：探讨新疆维吾尔族及汉族宫颈癌新辅助化疗前后P-gp、MRPI和GST-∏的表达及其与化疗疗效的关系。方法：运用S-P法检测分别检测维吾尔族妇女宫颈鳞癌组织22例和非宫颈鳞癌组织20例,汉族妇女宫颈鳞癌组织30例和非宫颈鳞癌组织30例,新辅助化疗前后P-gP、MRPI和GST-π的表达水平。结果：①新疆维吾尔族正常宫颈、初治宫颈癌组织中P-gp的阳性表达率分别为10%、72.7%;MRP1的阳性表达率分别为20%、40.9%;GST-π的阳性表达率分别为45%、90.9%。P-gp、和MRP1在各组间比较差异均有统计学意义（P〈0.05）,GST-π差异无统计学意义（P〉0.05）。②新疆汉族正常宫颈、初治宫颈癌组织中P-gp的阳性表达率分别为10%、56.7%;GST-π的阳性表达率分别为20%、60%,MRP1的阳性表达率分别为40%、86.7%。P-gp、GST-π和MRP1在各组间比较差异均有统计学意义（P〈0.05）。③在新疆维吾尔族妇女宫颈鳞癌组织中：NACT后宫颈癌组织中GST-π阳性表达显著上升（P〈0.05）,有统计学意义。NACT后宫颈癌组织中P-pg、MRP1阳性表达差异无统计学意义（P〉0.05）。④在新疆汉族妇女宫颈鳞癌组织中：NACT后宫颈癌组织中P-pg、GST-π阳性表达显著上升（P〈0.05）;有统计学意义。NACT后宫颈癌组织中MRP1阳性表达上升但差异无统计学意义（P〉0.05）。⑤新疆维吾尔族妇女化疗前宫颈鳞癌组织中MRP1及GST-π表达阴性和阳性患者NACT有效率无显著性差异（p〉0.05）,P-gp表达阴性患者NACT有效率显著高于P-gp表达阳性患者NACT有效率（p〈0.05）;⑥汉族化疗前宫颈鳞癌组织中P-gp、GST-π表达阴性患者NACT有效率显著高于P-gp、GST-π表达阳性患者NACT有效率（p〈0.05）;化疗前宫颈鳞癌MRP1表达阴性和阳性患者NACT有效率无显著性差异（p〉0.05）。结论：P-pg和GST-π可作为预测汉族宫颈鳞癌化疗敏感性指标。P-pg可作为预测维吾尔族宫颈鳞癌化疗敏感性指标。     

Study of a single BRCA2 mutation with high carrier frequency in a small population.

Germ-line changes in the cancer-predisposition gene BRCA2 are found in a small proportion of breast cancers. Mutations in the BRCA2 gene have been studied mainly in families with high risk of breast cancer in females, and male breast cancer also has been associated with BRCA2 mutations. The importance of germ-line BRCA2 mutations in individuals without a family history of breast cancer is unknown. The same BRCA2 mutation has been found in 16/21 Icelandic breast cancer families, indicating a founder effect. We determined the frequency of this mutation, 999del5, in 1,182 Icelanders, comprising 520 randomly selected individuals from the population and a series of 632 female breast cancer patients (61.4% of patients diagnosed during the study period) and all male breast cancer patients diagnosed during the past 40 years. We detected the 999del5 germ-line mutation in 0.6% of the population, in 7.7% of female breast cancer patients, and in 40% of males with breast cancer. The mutation was strongly associated with onset of female breast cancer at age <50 years, but its penetrance and expression are varied. A number of cancers other than breast cancer were found to be increased in relatives of mutation carriers, including those with prostate and pancreatic cancer. Furthermore, germ-line BRCA2 mutation can be present without a strong family history of breast cancer. Comparison of the age at onset for mother/daughter pairs with the 999del5 mutation and breast cancer indicates that age at onset is decreasing in the younger generation. Increase in breast cancer incidence and lower age at onset suggest a possible contributing environmental factor.     

Mutational analysis of breast/ovarian cancer hereditary predisposition gene BRCA1 in Tunisian women

BRCA1 is a breast cancer susceptibility gene. Germline mutations in BRCA1 gene are found in 5 to 10% of breast cancer. The aim of this study is to screen the tunisian women with familial or sporadic breast cancer for BRCA1 gene mutations. The authors used the Protein Truncation Test (PTT) and DNA sequencing to detect BRCA1 gene mutations in 12 tunisian families with breast cancer and the Allele Specific Oligonucleotide-PCR (ASO-PCR) to detect the 185delAG and 1294del40 mutations in 150 tunisian women with sporadic breast cancer. A nonsens mutation was found, by PTT, in exon 11 of BRCA1 gene in one case of familial breast cancer. No mutation in the rest of exons was found by the DNA sequencing. The BRCA1 1294del40 mutation was found only in a patient with non familial breast cancer. The 185delAG mutation was absent in all cases of breast cancer. These data suggest that the germline mutation of BRCA1 is implicated in breast cancer in Tunisia and that the 185delAG mutation is absent in arab tunisian women.     

Referral and experience with genetic testing among women with early onset breast cancer

The purpose of this study was to determine whether physicians refer women with early onset breast cancer for genetic testing for BRCA1 and BRCA2, and how women respond to being offered testing and use the results. A web-based survey was distributed to 1221 women with early onset breast cancer. The survey included 158 questions divided into the following sections: demographics, family history of cancer, medical history, treatment history, and experience with genetic testing. Of 551 women diagnosed since 1993 who responded to the survey (45.1%), less than half (45%, n = 246) had ever discussed genetic testing with their physician and/or been referred to see a genetic counselor. Women with a family history of cancer (53%) and Ashkenazi Jewish women (81%) were more likely to have been referred. Of those who had discussed testing, 60% had undergone or were interested in testing. Overall 92 women were tested and 19 (20.6%) of these tested positive for a deleterious BRCA1 or BRCA2 mutation. Fourteen (74%) who tested positive subsequently underwent prophylactic surgery. Satisfaction with counseling and the decision to be tested was high. Among women who were not offered testing, the fact that the test had not been offered by their physician (89%), and fear of discrimination (83%) were the two most frequently cited factors for lack of interest in testing. A substantial number of women are not being referred to genetic counseling and/or testing after a diagnosis of early onset breast cancer. Among those who were tested, there was high interest in prophylactic surgery after confirmation of a BRCA1/2 mutation.     

乳腺癌的p53免疫组织化学和PCR-SSCP研究

为了明确p53突变与乳腺癌临床特征的关系,研究了50例浸润性乳腺导管癌中p53免疫组织化学检测与临床指标肿瘤大小、淋巴结转移情况及病人年龄的关系,并探讨p53免疫组织化学结果与PCR-SSCP检测结果的关系及意义.发现p53免疫组织化学检测阳性与肿瘤大小及淋巴结转移关系密切(P＜0.05);1例p53免疫组织化学检测阳性病例PCR-SSCP检测为杂合突变,1例p53免疫组织化学检测阴性病例为PCR-SSCP检测p53纯合缺失.我们的结果提示免疫组织化学检测阳性并不一定有p53突变,而阴性则可能有p53基因缺失,临床上结合两种检测可提供更准确的p53状况的参考资料.     

BRCA1 mutations in a population-based study of breast cancer in Stockholm County

The mutation frequency of BRCA1 and BRCA2 in women with breast cancer varies according to family history, age at diagnosis and ethnicity. The contribution of BRCA1 and BRCA2 mutations in breast cancer populations, unselected for age and family history, has been examined in several studies reporting mutation frequencies between 1% and 12% by screening methods, population sizes, and to what extent the gene/s were screened differed in the studies. We wanted to clarify the proportion of breast cancer attributable to mutations in BRCA1 in an unselected breast cancer population from the Stockholm region. All incident breast cancer patients treated surgically in a 19-month period were eligible for the study and 70% (489/696) participated. Exon 11 of BRCA1 was screened for mutations using the protein truncation test, and the mutation frequency was estimated from that. In previous studies on high-risk families from Stockholm, more than 70% of the mutations were detected in exon 11. Two mutations were found, both in patients with a family history or their own medical history of ovarian cancer, giving a mutation frequency in exon 11 of 0.4% and an estimated BRCA1 mutation frequency of <1%. Mutations in BRCA1 in unselected breast cancer cases in our region are rare and likely to be found only in high-risk families. Our BRCA1 prevalence is the lowest of all studies on unselected breast cancer patients, probably reflecting the comparatively low rates detected also in high-risk breast cancer families from the region.     

Prevalence and penetrance of germline BRCA1 and BRCA2 mutations in a population series of 649 women with ovarian cancer

A population-based series of 649 unselected incident cases of ovarian cancer diagnosed in Ontario, Canada, during 1995-96 was screened for germline mutations in BRCA1 and BRCA2. We specifically tested for 11 of the most commonly reported mutations in the two genes. Then, cases were assessed with the protein-truncation test (PTT) for exon 11 of BRCA1, with denaturing gradient gel electrophoresis for the remainder of BRCA1, and with PTT for exons 10 and 11 of BRCA2. No mutations were found in all 134 women with tumors of borderline histology. Among the 515 women with invasive cancers, we identified 60 mutations, 39 in BRCA1 and 21 in BRCA2. The total mutation frequency among women with invasive cancers, 11.7% (95% confidence interval [95%CI] 9.2%-14.8%), is higher than previous estimates. Hereditary ovarian cancers diagnosed at age <50 years were mostly (83%) due to BRCA1, whereas the majority (60%) of those diagnosed at age >60 years were due to BRCA2. Mutations were found in 19% of women reporting first-degree relatives with breast or ovarian cancer and in 6.5% of women with no affected first-degree relatives. Risks of ovarian, breast, and stomach cancers and leukemias/lymphomas were increased nine-, five-, six- and threefold, respectively, among first-degree relatives of cases carrying BRCA1 mutations, compared with relatives of noncarriers, and risk of colorectal cancer was increased threefold for relatives of cases carrying BRCA2 mutations. For carriers of BRCA1 mutations, the estimated penetrance by age 80 years was 36% for ovarian cancer and 68% for breast cancer. In breast-cancer risk for first-degree relatives, there was a strong trend according to mutation location along the coding sequence of BRCA1, with little evidence of increased risk for mutations in the 5' fifth, but 8.8-fold increased risk for mutations in the 3' fifth (95%CI 3.6-22.0), corresponding to a carrier penetrance of essentially 100%. Ovarian, colorectal, stomach, pancreatic, and prostate cancer occurred among first-degree relatives of carriers of BRCA2 mutations only when mutations were in the ovarian cancer-cluster region (OCCR) of exon 11, whereas an excess of breast cancer was seen when mutations were outside the OCCR. For cancers of all sites combined, the estimated penetrance of BRCA2 mutations was greater for males than for females, 53% versus 38%. Past studies may have underestimated the contribution of BRCA2 to ovarian cancer, because mutations in this gene cause predominantly late-onset cancer, and previous work has focused more on early-onset disease. If confirmed in future studies, the trend in breast-cancer penetrance, according to mutation location along the BRCA1 coding sequence, may have significant impact on treatment decisions for carriers of BRCA1-mutations. As well, BRCA2 mutations may prove to be a greater cause of cancer in male carriers than previously has been thought.     

Identification of a Comprehensive Spectrum of Genetic Factors for Hereditary Breast Cancer in a Chinese Population by Next-Generation Sequencing

The genetic etiology of hereditary breast cancer has not been fully elucidated. Although germline mutations of high-penetrance genes such as BRCA1/2 are implicated in development of hereditary breast cancers, at least half of all breast cancer families are not linked to these genes. To identify a comprehensive spectrum of genetic factors for hereditary breast cancer in a Chinese population, we performed an analysis of germline mutations in 2,165 coding exons of 152 genes associated with hereditary cancer using next-generation sequencing (NGS) in 99 breast cancer patients from families of cancer patients regardless of cancer types. Forty-two deleterious germline mutations were identified in 21 genes of 34 patients, including 18 (18.2%) BRCA1 or BRCA2 mutations, 3 (3%) TP53 mutations, 5 (5.1%) DNA mismatch repair gene mutations, 1 (1%) CDH1 mutation, 6 (6.1%) Fanconi anemia pathway gene mutations, and 9 (9.1%) mutations in other genes. Of seven patients who carried mutations in more than one gene, 4 were BRCA1/2 mutation carriers, and their average onset age was much younger than patients with only BRCA1/2 mutations. Almost all identified high-penetrance gene mutations in those families fulfill the typical phenotypes of hereditary cancer syndromes listed in the National Comprehensive Cancer Network (NCCN) guidelines, except two TP53 and three mismatch repair gene mutations. Furthermore, functional studies of MSH3 germline mutations confirmed the association between MSH3 mutation and tumorigenesis, and segregation analysis suggested antagonism between BRCA1 and MSH3. We also identified a lot of low-penetrance gene mutations. Although the clinical significance of those newly identified low-penetrance gene mutations has not been fully appreciated yet, these new findings do provide valuable epidemiological information for the future studies. Together, these findings highlight the importance of genetic testing based on NCCN guidelines and a multi-gene analysis using NGS may be a supplement to traditional genetic counseling.     

Detection of eight BRCA1 mutations in 10 breast/ovarian cancer families, including 1 family with male breast cancer.

Genetic epidemiological evidence suggests that mutations in BRCA1 may be responsible for approximately one half of early onset familial breast cancer and the majority of familial breast/ovarian cancer. The recent cloning of BRCA1 allows for the direct detection of mutations, but the feasibility of presymptomatic screening for cancer susceptibility is unknown. We analyzed genomic DNA from one affected individual from each of 24 families with at least three cases of ovarian or breast cancer, using SSCP assays. Variant SSCP bands were subcloned and sequenced. Allele-specific oligonucleotide hybridization was used to verify sequence changes and to screen DNA from control individuals. Six frameshift and two missense mutations were detected in 10 different families. A frameshift mutation was detected in a male proband affected with both breast and prostate cancer. A 40-bp deletion was detected in a patient who developed intra-abdominal carcinomatosis 1 year after prophylactic oophorectomy. Mutations were detected throughout the gene, and only one was detected in more than a single family. These results provide further evidence that inherited breast and ovarian cancer can occur as a consequence of a wide array of BRCA1 mutations. These results suggests that development of a screening test for BRCA1 mutations will be technically challenging. The finding of a mutation in a family with male breast cancer, not previously thought to be related to BRCA1, also illustrates the potential difficulties of genetic counseling for individuals known to carry mutations.     

Haplotype and phenotype analysis of six recurrent BRCA1 mutations in 61 families: results of an international study.

Several BRCA1 mutations have now been found to occur in geographically diverse breast and ovarian cancer families. To investigate mutation origin and mutation-specific phenotypes due to BRCA1, we constructed a haplotype of nine polymorphic markers within or immediately flanking the BRCA1 locus in a set of 61 breast/ovarian cancer families selected for having one of six recurrent BRCA1 mutations. Tests of both mutations and family-specific differences in age at diagnosis were not significant. A comparison of the six mutations in the relative proportions of cases of breast and ovarian cancer was suggestive of an effect (P = .069), with 57% of women presumed affected because of the 1294 del 40 BRCA1 mutation having ovarian cancer, compared with 14% of affected women with the splice-site mutation in intron 5 of BRCA1. For the BRCA1 mutations studied here, the individual mutations are estimated to have arisen 9-170 generations ago. In general, a high degree of haplotype conservation across the region was observed, with haplotype differences most often due to mutations in the short-tandem-repeat markers, although some likely instances of recombination also were observed. For several of the instances, there was evidence for multiple, independent, BRCA1 mutational events.